Brake lever device for bicycles

ABSTRACT

The invention relates to a brake lever device for use on the handlebar of a bicycle. With conventional brake lever devices, the center of rotation of the brake lever is a large distance away from the axis of the handlebar, radially outwardly of the bar, and the Bowden cable connected to the lever is correspondingly projected and is very likely to be caught by an obstacle, while the arrangement involves waste of materials. Accordingly, to position the center (O) of rotation of a brake lever (43) close to the central axis of the handlebar (1), a pivot (4) for the brake lever (43) is positioned perpendicular to the central axis (C) of a handlebar inserting bore (5) of a brakcet (2).

TECHNICAL FIELD

The present invention relates to a brake lever device for use on thehandlebar of a bicycle.

BACKGROUND ART

FIG. 21 shows a conventional brake lever device, which comprises abracket 42 mounted on a handlebar 41, and a brake lever 43 mounted onthe bracket and pivotally movable about an axis 0. The bracket 42 has aportion 44 for holding the outer wire of a Bowden cable 49, and thebrake lever 43 is provided with a portion 45 for holding the inner wireof the cable (see Examined Japanese Utility Model Publication SHO60-3383).

With the above conventional brake lever device, the center 0 of movementof the brake lever 43 is at a large distance S from the central axis Cof the handlebar 41 radially outwardly of the bar as illustrated.Accordingly, the brake lever device is projected radially outward fromthe handlebar 41 by an amount corresponding to the distance. Theportions 44, 45 for holding the Bowden cable 49 are therefore projectedfrom the handlebar 41 radially outward, so that the Bowden cable 49 iscorrespondingly likely to become engaged with an obstacle or the likewhile the bicycle is driven, hence hazardous. Moreover, the device inits entirety undesirably has a large size involving waste of materials.

Further if the distance L between the brake lever 43 and the handlebar41 is definite, the brake becomes difficult to operate depending on thesize of the rider's hand. Accordingly, an adjusting bolt 46 screwedthrough the bracket 42 in bearing contact with the brake lever 43 isturned and thereby moved axially thereof to alter the position ofcontact of the bolt 46 with the brake lever 43 and vary the openingdistance L for the brake lever 43 for adjustment (see Examined JapaneseUtility Model Publication SHO 56-14424).

With the conventional brake lever device described, the adjusting bolt46 is positioned in a narrow space between the Bowden cable 49 and thehandlebar 41 and is therefore difficult to move for adjustment. Thearrangement is further unsightly.

The spacing between the wheel rim of the bicycle and the brake shoes,which must be maintained at the proper value, varies if the brake shoewears or the opening distance L of the brake lever 43 is altered. Insuch a case, there arises a need to adjust the length of the inner wire,whereas the conventional device is not provided with means for readilyadjusting the length of the inner wire, which therefore requires acumbersome adjusting procedure.

The object of the present invention is to overcome the foregoingproblems.

DISCLOSURE OF THE INVENTION

To solve the problems of the prior art, the present invention provides abrake lever device for bicycles which includes a bracket 2 mountable ona handlebar 1 and a brake lever 3 pivotally movably mounted on thebracket, the bracket 2 having a portion for holding the outer wire of aBowden cable 19, the brake lever 3 having a portion for holding theinner wire of the cable. First, the device is characterized in that thebracket 2 has a bore 5 for removably inserting the handlebar 1therethrough, a pivot 4 being positioned substantially perpendicular tothe central axis C of the inserting bore 5, the brake lever 3 beingmounted on the pivot 4 and movable about the axis thereof.

In addition to the first feature, the device has the second feature thatthe outer wire holding portion 2B is provided with a screw tube 18movable axially thereof by turning an adjusting nut 15 screwed thereonfor adjusting the opening width of the brake lever, the adjusting screwtube 18 having the inner wire 16 inserted therethrough, the adjustingscrew tube 18 being in contact at its one end with the end of the innerwire holding portion 3E opposed to the outer wire holding portion 2B.

In addition to the first feature, the device has the third feature thatthe inner wire holding portion 3E is provided with an inner wireadjusting screw 25 movable axially thereof by turning an adjusting nut27 screwed thereon, the adjusting screw 25 having the inner wire 16inserted therethrough and engaging the inserted end thereof.

The fourth feature of the device is the combination of the first featurewith the second and third features.

In addition to the first and second features, the device has the fifthfeature that the other end of the adjusting screw tube 18 is joined toan outer wire holding tube 21 so as to be movable therewith in the axialdirection.

In addition to the fourth feature, the device has the sixth feature thatthe other end of the adjusting screw tube 18 is joined to an outer wireholding tube 21 so as to be movable therewith in the axial direction.

According to the first feature of the invention, the center of pivotalmovement of the brake lever 43 is not a large distance radiallyoutwardly away from the central axis of the handlebar 1, so that theportions for holding the Bowden cable 19 can be positioned close to thehandlebar 1 to the greatest possible extent. This diminishes thelikelihood that the Bowden cable 19 will be caught by an obstacle or thelike, further compacting the device in its entirety to eliminate thewaste of materials.

In addition to the advantage afforded by the first feature, the secondfeature assures that the opening width of the brake lever 43 isadjustable by axially moving the adjusting screw tube 18 along the cable19, on the outer wire holding portion 2B of the bracket 2. Unlike theconventional arrangement, therefore, the adjusting nut 15 for axiallymoving the screw tube 18 need not be positioned in the narrow spacebetween the Bowden cable 19 and the handlebar 1, hence facilitatedadjustment. The screw tube 18 which is precluded from projecting beyondthe bracket 2 ensures a favorable appearance.

According to the third feature in combination with the advantageafforded by the first feature, the adjusting nut 27, when turned, movesthe adjusting screw 27 axially thereof along the inner wire 16 to adjustthe length of the inner wire 16 which is engaged with the screw 25,whereby the spacing between the tire rim and the brake shoes isadjustable efficiently.

According to the fourth feature, the advantages of the second and thirdfeatures are available in combination.

The fifth feature affords the following advantage in addition to theadvantage given by the second feature. When the opening width of thebrake lever 3 is altered, the spacing between the tire rim and the brakeshoes also varies. According to the fourth feature described, thespacing between the tire rim and the brake shoe must be adjustedindependently of the adjustment of the opening width of the brake lever3, whereas if the outer wire holding tube 21 is made movable with theadjusting screw tube 18, the alteration of the opening width of thebrake lever 3 produces no change in the relative relation between theouter wire and the inner wire, consequently resulting in no variation inthe spacing between the tire rim and the brake shoes and eliminating theneed to adjust the spacing. Thus the lever opening width is adjustableefficiently.

The sixth feature provides in combination the advantages afforded by thethird and fifth features. More specifically, the opening width of thebrake lever is adjustable easily with a higher efficiency. If the brakeshoes wear away, the spacing between the rim and the shoes is adjustableefficiently.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 8 show a first embodiment of the present invention. FIG. 1 isa plan view; FIG. 2 is a front view; FIG. 3 is a bottom view partlybroken away; FIG. 4 is a view in section taken along the line 4--4 inFIG. 3; FIG. 5 is a plan view of a bracket; FIG. 6 is a front view ofthe bracket; FIG. 7 is a plan view of a brake lever; and FIG. 8 is afront view of the brake lever.

FIGS. 9 to 20 show a second embodiment of the invention. FIG. 9 is aplan view; FIG. 10 is a front view; FIG. 11 is a bottom view partlybroken away; FIG. 12 is a view in section taken along the line 12--12 inFIG. 11; FIG. 13 is a plan view of a bracket; FIG. 14 is a front view ofthe bracket; FIG. 15 is a plan view of a brake lever; FIG. 16 is a frontview of the brake lever; FIG. 17 is a fragmentary enlarged sectionalview of FIG. 11; FIG. 18 is a view in section taken along the line18--18 in FIG. 17; FIG. 19 is a sectional view taken along the line19--19 in FIG. 17; and FIG. 20 is a view in section taken along the line20 in FIG. 17.

FIG. 21 is a schematic plan view of a conventional device.

BEST MODE OF CARRYING OUT THE INVENTION

A first mode of practicing the present invention will be described withreference to FIGS. 1 to 8.

Referring to these drawings, indicated at 1 is the handlebar of abicycle, at 2 a bracket mounted on the handlebar 1, and at 3 a brakelever rotatably mounted on a pivot 4.

As seen in FIGS. 5 and 6, the bracket 2 has a generally sphericalhandlebar gripping portion 2A formed with a bore 5 for inserting thehandlebar therethrough, and a portion 2B for holding the outer wire of aBowden cable, the holding portion extending from the gripping portion 2Aradially outwardly of the handlebar 1 and slanting with respect to theaxis of the handlebar. The gripping portion 2A has a planar face 6 inparallel to the central axis C of the handlebar inserting bore. Athreaded hole 7 for the pivot 4 is formed in the planar portion 6. Theaxis 0 of the pivot 4 intersects the central axis C of the bore at rightangles therewith. A dividing groove 8 parallel to the planar face 6 isformed in the gripping portion 2A in communication with the insertingbore 5. The gripping portion is formed with a head cavity 10, a shankhole 11 and a threaded hole 12 for a fastening bolt 9 across the groove8 at right angles therewith. Accordingly, the fastening bolt 9 isprecluded from projecting beyond the outer surface of the grippingportion 2A of the bracket 2.

To provide the fastening bolt 9, the bore 5 for inserting the handlebar1 is made eccentric with respect to the center of the spherical grippingportion 2A for a reduction in weight and from the viewpoint of design,but the eccentricity is not limitative.

The outer wire holding portion 2B is formed with a bore 13 havinginserted therethrough a screw tube for adjusting the opening width ofthe brake lever, the bore 13 being inclined with respect to the centralaxis C of the handlebar inserting bore. A cutout 14 having an adjustingnut 15 fitted therein is formed in the portion 2B at right angles withthe insertion bore 13. The adjusting nut 15 is screwed on the adjustingscrew tube 18 which is hollow and has a bore 17 for inserting an innerwire 16 therethrough. An outer wire holding tube 21 for attachingthereto one end of the outer wire 20 of the Bowden cable 19 is fitted inone open end of the screw tube insertion bore 13.

With reference to FIGS. 7 and 8, the brake lever 3 includes a mountportion 3A and a grip portion 3B which are generally in an L-shapedarrangement. The mount portion 3A has a hole 22 for inserting the pivot4 therethrough.

The corner of the L-shaped lever serves as an inner wire holding portion3E and has a bore 23 extending therethrough for an inner wire adjustingscrew. The lever is formed at its base end with a concave face 3C alongthe bracket 2 and having a slightly larger radius than the sphericalsurface of the bracket 2 so that the brake lever 3 will not interferewith the bracket 2 even when moved about the pivot 4.

The horizontal central axis 3D of the grip portion 3B of the brake lever3 is positioned in the same plane as the central axis C of the handlebarinserting bore. The horizontal axis 23A of the inner wire adjustingscrew inserting bore 23 is positioned in the same plane as thehorizontal axis 13A of the screw tube insertion bore 13 of the bracket2. The lever central axis 3D is parallel to the horizontal axes 13A and23A.

The grip portion of the brake lever 3 has a thickness graduallydecreasing toward its outer end and is smoothly curved by eliminatingcorners so as not to feel ragged when touched by hand. The head 4A ofthe pivot 4 is almost unprojected beyond the outer side surface of themount portion 3A of the brake lever 3.

Indicated at 24 is a hole for inserting therethrough a tool forfastening the bolt 9.

The inner wire adjusting screw, which is tubular and indicated at 25,has an outer peripheral portion cut out in parallel to the axis toprovide a planar portion 25A. When the adjusting screw 25 is inserted inthe bore 23, a setscrew screwed in the lever at right angles with thebore 23 bears against the screw 25, permitting the screw 25 to moveaxially thereof without rotating. The adjusting screw 25 is projectedtoward the grip portion 3B of the brake lever 3, and an inner wireadjusting nut 27 is screwed on the projected portion. The inner wire 16is inserted in the nut 27 and has an end member 28 which is retainedwithin the nut 27. Indicated at 29 is a wave washer.

The base end face of the brake lever 3 having the bore 23 is in contactwith the head face 18A of the adjusting screw tube 18. The adjusting nut15, when rotated, moves the screw tube 18 axially thereof to adjust thedistance between the outer wire holding portion 2B of the bracket 2 andthe brake lever 3, i.e. the opening width of the brake lever 3.

Further the inner wire adjusting nut 27, when rotated, moves theadjusting screw 25 axially thereof, whereby the length of the inner wire16 is adjustable optimally.

The Bowden cable outer wire holding portion 2B of the bracket 2 and theportion of the brake lever 3 around the inserting bore 23 which servesto hold the inner wire of the cable are arranged on a circumferencecentered about the pivot 4.

According to the foregoing embodiment, the center 0 of pivotal movementof the brake lever 3 is close to the central axis of the handlebarinserting bore 5, i.e. to the central axis C of the handlebar 1, so thatthe Bowden cable holding portions are positioned close to the handlebarto the greatest possible extent. This diminishes the likelihood that thecable 19 will be caught by an obstacle or the like.

The head of the fastening bolt 9 for the bracket 2 is positioned in thecavity 10 in the lower side of the bracket without projecting, while thehead 4A of the pivot 4 is almost unprojected from the brake lever. Thebrake lever therefore has a neat appearance, feels good and is easy tograsp.

Ideally, the axis 0 of rotation of the brake lever 3 should bepositioned on the central axis C of the handlebar inserting bore 5, butcan be positioned in the vicinity of the axis C depending on the design.

According to the present embodiment the Bowden cable holding portions ofthe bracket 2 and the brake lever 3 can be positioned closer to therotation axis 0 to further diminish the amount of projection thereof bysuitably determining the angle between the central axes 13A, 23A of thebores 13, 23 and the distance of the brake lever 3 from the rotationaxis 0.

The position where the fastening bolt 9 is attached to the bracket 2 maybe so selected that the brake lever 3 will not become an obstacle whenthe bolt is fastened.

A second mode of practicing the invention will be described withreference to FIGS. 9 to 20.

Referring to these drawings, indicated at 1 is the handlebar of abicycle, at 2 a bracket mounted on the handlebar 1, and at 3 a brakelever rotatably mounted on a pivot 4.

As seen in FIG. 13 and FIG. 14, the bracket 2 has a generally sphericalhandlebar gripping portion 2A formed with a bore 5 for inserting thehandlebar therethrough, and a portion 2B for holding an outer wire, theholding portion extending from the gripping portion 2A radiallyoutwardly of the handlebar 1. The gripping portion 2A has a face 6 whichis planar and in parallel to the central axis C of the handlebarinserting bore. A threaded hole 7 is formed in the planar portion 6 forattaching the pivot 4. The axis 0 of the pivot 4 intersects the centralaxis C of the bore at right angles therewith. A dividing groove 8parallel to the planar face 6 is formed in the gripping portion 2A incommunication with the inserting bore 5. The gripping portion is formedwith a head cavity 10, a shank hole 11 and a threaded hole 12 for afastening bolt 9 across the groove 8 at right angles therewith.Accordingly, the fastening bolt 9 is precluded from projecting beyondthe outer surface of the gripping portion 2A of the bracket 2.

To provide the fastening bolt 9, the bore 5 for inserting the handlebar1 is made eccentric with respect to the center of the spherical grippingportion 2A for a reduction in weight and from the viewpoint of design,but the eccentricity is not limitative.

The outer wire holding portion 2B is formed with a bore 13 havinginserted therethrough a screw tube for adjusting the opening width ofthe brake lever, the bore 13 being inclined with respect to the centralaxis C of the handlebar inserting bore. A cutout 14 having an adjustingnut 15 fitted therein is formed in the portion 2B at right angles withthe insertion bore 13. The adjusting nut 15 is screwed on the adjustingscrew tube 18 which is hollow and has a bore 17 for inserting an innerwire 16 therethrough. The head 18A of the screw tube 18 has a taperedface. Except for the head 18A, the screw tube 18 has a peripheralportion cut out over its entire length to provide a planar face 18Bparallel to the horizontal axis 13A of the bore 13 as seen in FIGS. 17to 19 and is therefore in the form of a partly cut-out circle in crosssection. The screw tube insertion bore 13 has the same cut-out circularcross section as the screw tube 18. Thus, the screw tube 18 insertedthrough the bore 13 is slidable only axially thereof without rotation.

The forward end of the insertion bore 13 is enlarged to provide a cavity13B. A tube 21 holding one end of the outer wire 20 of the Bowden wire19 has its one end fitted in the cavity 13B axially movably. This end ofthe outer wire holding tube 21 is internally threaded as at 21A and isscrewed on and thereby joined to the end 18C of the screw tube 18.Accordingly, the adjusting nut 15, when rotated, moves the screw tube 18axially thereof, and the holding tube 21 moves at the same time by thesame amount as the screw tube 18.

With reference to FIGS. 15 and 16, the brake lever 3 includes a mountportion 3A and a grip portion 3B which are generally in an L-shapedarrangement. The mount portion 3A has a hole 22 for inserting the pivot4 therethrough.

The corner of the L-shaped lever serves as an inner wire holding portion3E and has a bore 23 extending therethrough for an inner wire adjustingscrew. The lever is formed at its base end with a concave face 3C alongthe bracket 2 and having a slightly larger radius than the sphericalsurface of the bracket 2 so that the brake lever 3 will not interferewith the bracket 2 even when moved about the pivot 4.

The horizontal central axis 3D of the grip portion 3B of the brake lever3 is positioned in the same plane as the central axis C of the handlebarinserting bore. The horizontal axis 23A of the inner wire adjustingscrew inserting bore 23 is positioned in the same plane as thehorizontal axis 13A of the screw tube insertion bore 13 of the bracket2. The lever central axis 3E is parallel to the horizontal axes 13A and23A.

The grip portion of the brake lever 3 has a thickness graduallydecreasing toward its outer end and is smoothly curved by eliminatingcorners so as not to feel ragged when touched by hand. The head 4A ofthe pivot 4 is almost unprojected beyond the outer side surface of themount portion 3A of the brake lever 3.

Indicated at 24 is a hole for inserting therethrough a tool forfastening the bolt 9.

The inner wire adjusting screw, which is tubular and indicated at 25,has an outer peripheral portion cut out in parallel to the axis toprovide a planar portion 26. The adjusting screw 25 as inserted in thebore 23 is movable in the axial direction without rotating. Theadjusting screw 25 is projected toward the grip portion 3B of the brakelever 3, and an inner wire adjusting nut 27 is screwed on the projectedportion. The inner wire 16 is inserted in the nut 27 and has an endmember 28 which is retained within the nut 27. Indicated at 29 is a wavewasher.

The base end of the brake lever 3 having the inner wire adjusting screwinserting bore 23 is formed with an outwardly flaring tapered face 30,and the tapered end face of the head 18A of the screw tube 18 is inintimate contact with the tapered face 30. The adjusting nut 14, whenrotated, axially moves the screw tube 18 to adjust the distance betweenthe outer wire holding portion 2B of the bracket 2 and the brake lever3, i.e. the opening width of the brake lever 3.

Further the inner wire adjusting nut 27, when rotated, moves theadjusting screw 25 axially thereof, whereby the length of the inner wire16 is adjustable optimally.

The outer wire holding portion 2B and the inner wire holding portion 3Efor the Bowden wire 19 are arranged on a circumference centered aboutthe pivot 4.

The pivot hole 22 in the brake lever 3 has such a diameter as to looselyfit around the pivot 4 a coiled return spring 31 for the lever 3. Theinner periphery defining the hole 22 is threaded as at 22A, and a ring32 for adjusting the tension of the return spring is screwed in theinternally threaded portion 22A of the hole. The return spring 31 hasone end engaged in a cavity 33 in the bracket 2 and the other end fittedin a spring engaging recess 34 in the upper edge of the ring 32. Thering 32 has at its one end a flange 32A formed with stepped portions 35for engaging a turning tool. The tension of the return spring 31 isvariable by rotating the ring 32. Accordingly, when the brake lever 3 isreleased after a braking action, the lever 3 is smoothly returned to itsinitial position not only by the tension of the inner wire 16 but alsoby the elastic force of the spring 31 to move the brake shoes away fromthe rim.

According to the embodiment described, the adjusting nut 15, whenrotated, axially moves the screw tube 18 to vary the face-to-facedistance S between the outer wire holding portion 2B and the inner wireholding portion 3E, whereby the opening width W of the brake lever 3 isadjustable as desired. At this time, the screw tube 18 moves with theouter wire holding tube 21 with its head 18A in contact with the taperedface 30 of the inner wire holding portion 3E, so that the inner wire 16and the outer wire 20 do not move relative to each other, permitting thespacing between the rim of the bicycle and the brake shoes to remainunchanged, hence no need to adjust the outer wire 20.

The head of the fastening bolt 9 for the bracket 2 is positioned withinthe head cavity 10 in the lower side of the bracket without projecting,while the head 4A of the pivot 4 is almost unprojected from the lever 3.The brake lever therefore has a neat appearance, feels good and is easyto grasp.

Furthermore, the Bowden wire holding portions are not projected greatlyradially outwardly of the handlebar 1, permitting the cable 19 to extendalong the handlebar 1. This diminishes the possible hazard.

Ideally, the axis 0 of rotation of the brake lever 3 should bepositioned on the central axis C of the handlebar inserting bore 5, butcan be positioned in the vicinity of the axis C depending on the design.

According to the present embodiment, the Bowden cable holding portionsof the bracket 2 and the brake lever 3 can be positioned closer to therotation axis 0 to further diminish the amount of projection thereof bysuitably determining the angle between the central axis 13A, 23A of thebores 13, 23 and the distance of the brake lever 3 from the rotationaxis 0.

The position where the fastening bolt 9 is attached to the bracket 2 maybe so selected that the brake lever 3 will not become an obstacle whenthe bolt is fastened.

INDUSTRIAL APPLICATION

The present invention is applicable to brake lever devices for use onthe handlebars of bicycles.

I claim:
 1. A brake lever device for bicycles, including a bracketmountable on a handlebar and a brake lever pivotally movably mounted onthe bracket, the bracket having an outer wire holding portion forholding the outer wire of a Bowden cable, the brake lever having aninner wire holding portion for holding the inner wire of the cable, thedevice being characterized in that the bracket has an inserting borethrough which the handlebar is removably insertable, a pivot beingpositioned substantially perpendicular to the central axis of theinserting bore, the brake lever being mounted on the pivot and beingmovable about the axis thereof, wherein the outer wire holding portionis provided with an outer wire adjusting screw tube that is axiallymovable by turning an adjusting nut screwed thereon for adjusting theopening width of the brake lever, the adjusting screw tube having theinner wire inserted therethrough, and the adjusting screw tube being incontact at one end with an end of the inner wire holding portion whichis disposed opposite the outer wire holding portion.
 2. A brake leverdevice for bicycles as defined in claim 1, wherein the inner wireholding portion is provided with an inner wire adjusting screw that isaxially movable by turning an adjusting nut screwed thereon, theadjusting screw having the inner wire inserted therethrough and engagingthe inserted end thereof.
 3. A brake lever device for bicycles asdefined in claim 1, wherein the other end of the adjusting screw tube isjoined to an outer wire holding tube so as to be movable therewith inthe axial direction.
 4. A brake lever device for bicycles, including abracket mountable on a handlebar and a brake lever pivotally movablymounted on the bracket, the bracket having an outer wire holding portionfor holding the outer wire of a Bowden cable, the brake lever having aninner wire holding portion for holding the inner wire of the cable,wherein the outer wire holding portion is provided with an adjustingscrew tube that is axially movable by turning an adjusting nut screwedthereon for adjusting the opening width of the brake lever, theadjusting screw tube having the inner wire inserted therethrough, theadjusting screw tube being in contact at one end with an end of theinner wire holding portion that is disposed opposite the outer wireholding portion, the inner wire holding portion being provided with aninner wire adjusting screw that is axially movable by turning anadjusting nut screwed thereon, and the adjusting screw having the innerwire inserted therethrough and engaging the inserted end thereof.
 5. Abrake lever device for bicycles as defined in claim 4, wherein the otherend of the adjusting screw tube is joined to an outer wire holding tubeso as to be movable therewith in the axial direction.